Rocket propulsion is a method of moving a vehicle, like a rocket, by expelling gas at high speed from its engines. This process follows Newton's Third Law of Motion, which states that for every action, there is an equal and opposite reaction. When the rocket pushes gas downward, it moves upward. The engines burn fuel, creating hot gases that expand and are forced out through a nozzle. This expulsion generates thrust, allowing the rocket to overcome Earth's gravity and travel into space. Different types of fuels, such as liquid or solid propellants, can be used to achieve the necessary power for flight.